Issues with Boundary Surface

Grasshopper
1

Hello everyone !

I encountered an issue with the Boundary surface component.

It seems that when I feed a planar curve into this component the curve get simplified and I’m missing a few vertices and edges in the final surface. How can I avoid that ? In the definition I attached, there is an example of the result I want to achieve, that I managed to recreate with a Python code. But I would like to avoid using any script in my definition.

Any explanation for this behavior or workaround will be greatly appreciated. Thanks !
IssueWithBoundarySurface.gh (5.0 KB)
Loïc

2

So to clarify, your Python requires R8.

Given this list of points:

            {0;0;1;0}
0. {6, 0, 0}
1. {3, 0, 0}
2. {3, 6, 0}
3. {6, 6, 0}
4. {6, 3, 0}

Boundary produces a surface without the the last point (middle of right side) from DeBrep while your Python shows that point.

boundary
boundary698×360 30.7 KB

Your Python:

import rhinoscriptsyntax as rs

a = rs.AddPlanarSrf(x)

You have the original points, Explode polyline shows the point, so innovate a solution :exclamation:

P.S. This copy is compatible with R7 Python. Works in R8 too.

pyBoundary_2024Jul16a
pyBoundary_2024Jul16a792×383 36.8 KB

pyBoundary_2024Jul16a.gh (7.6 KB)

3

Thank you Joseph,

Now that I look back to it, my question was not super clear…

your Python requires R8.

I did not think of that. Thanks for providing a script that is compatible with rhino 7.

As for a solution I still did not find one, I tried the component Fragment Patch but still no results :cry:.
Loïc

4

Other than Python, so use that.

5

Hi @Loïc2 ,

I believe Fragement Patch and Boundary Surfaces are intended to work this way and do some clean up inside the code.

In my opinion the way it operates is the preferred method or else you would have to create additional script logic to always clean up these kinds of surfaces (usually you don’t want the extra vertices on colinear edges… usually)

Why if I may ask?

You can always compile it as a component, wrap it in a cluster / user object if you want more control over it to “act” like a typical GH component.

EDIT:

Actually it seems that the Boundary Surfaces component may not do as much cleanup as I thought, looks like the Polyline component is causing the results you are seeing? Hmm… not quite sure but see below.

If you REALLY do need it as Grasshopper only… you can do it two ways like this:

image
image960×490 48.8 KB

Hope that helps

20240717_IssueWithBoundarySurface_Response_01a.gh (9.1 KB)